Thrust reversing and speed control for jet propulsion engines



May 30, 1950 A. w. MARTIN 2,509,238

'mRus'r REVERSING AND SPEED CONTROL FOR JET PROPULSION ENGINES Filed July 31, 1947 l2 (CONTROL) MofoR INVENT OR. ARNOLD WOODS MARTIN Patented May 30, 1950 UNITED STATES PATENT OFFICE THRUST REVERSING AND SPEED CONTROL FOR JET PROPULSION ENGINES (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 7 Glaims.

This invention relates to new and useful improvements in speed control mechanism for jetpropelled aircraft and other vehicles by means of directional control of the gas discharge.

in jet propulsion, when the expanding products of combustion are discharged through a restricted nomle, the propulsive force is proportionate to the rate of combustion and the volume and velocity of the discharge. Instead of changing the combustion rate, it is sometimes more advantageous to control the volume, velocity or direction of the discharge. It is particularly desirable to slow down jet-propelled aircraft immediately hetore or after landing. This desideratum is etiected in the device of this invention by a mechanism which changes the volume of the propulsive discharge by diverting a gradually increasing portion of it in the opposite direction.

The principal object of this invention is to provide a secondary speed control mechanism for jet-propelled aircraft consisting of a variable jet reversing means, so as to increase or decrease landing speed.

another object or this invention is to provide controllable means to vary the mass and velocity oi the jet discharge without changing the rate of combustion.

rind another object of this invention is to Provide quick-acting power operated mechanism to vary the propulsive or retarding iorce of the jet discharge without changing the rate of combustion.

And still another object of this invention is to proportionately close or open the propulsive or retarding jet discharge openings relatively and quickly by power actuation without regulating the rate of combustion.

A further object of this invention is to provide mechanically operated reversing jet discharge mechanism that is sealed against leakage in the opposite direction when the discharge is on either full propulsion or full retardation.

These and other objects of this invention, and the various features and details of the construction, operation and use thereof are hereinafter more fully set forth and described with reference to the accompanying drawing, in which like numbers refer to like parts and in which:

Fig. i is an isometric view of a jet propulsion power plant nozzle and orifice showing a longitudinally movable jet reversing ring mounted on power operated positioning rods.

Fig. 2 is a sectional view of the aft position of the power plant showing the line of flow of gases from the nozzle and through its orifice with the reversing ring in both the normal thrust producing position and also in the full retardin position thrust, the latter shown in dotted lines.

Referring now to the drawing and more particularly to Fig. 1 thereof, numeral i indicates a transversely positioned movable annular ring the position of which determines the amount of normal thrust or retardation. Numeral 2 refers to the nozzle used to direct the flow of gases from the combustion chamber (not shown) to the orifice formed by the annular ring i and the cone shaped member 3. Plates t are secured to said annular ring i and by capscrews 5 to rod 6, which are supported by and slide in brackets l to longitudinally adjust ring i with respect to the cone shaped member 3. Sprockets 8 and 8' are supported by brackets t and 9, respectively, and the sprockets 8 by means of a screw it and nut it action with rods t, move said rods t longitudinally through their supporting brackets l and thereby adjust ring i with respect to the cone shaped member 3. Sprocket chain in meshes with sprockets t, 8' and B" and is driven by motor i i which is connected to the sprocket t" by a long nut i6. Bracket it supports motor it from the nozzle casing i. As motor ii revolve it drives sprockets t and sprocket chain it) which 2 and through the annular orifice formed by ring i and cone shaped member 3 under the normal condition or thrust, while the dotted vectors ii indicate the direction of flow of the gases when the thrust is reversed by means of the movement of ring i longitudinally with respect to cone member 3 to the dotted position i. In the extreme rearward position of the ring i, its leading edge is in sealing relation with the trailing edge of the nozzle 2, while in its extreme forward position the throat of ring i is in engagement with the surface of the cone shaped member it.

It is to be understood that various modifications and changes may be made in this invention without departing from the spirit and scope thereof as set forth in the appended claims.

The invention described herein may be manufractured and used by the Government oi. the United States of America for governmental purposes without the payment of any royalties thereon or therefor;

3 What I claim is: 1. In combintion with a Jet propulsion power nozzle, a mechanism for regulating the speed of Jet-propelled aircraft by gradually reversing the direction of discharge, comprising a convergent annular nozzle section having an axially movable outer wall section at the rear end of said nozzle with a trailing external flange curved outwardly and forwardly to reverse the flow of discharge gases directed along the outside 'of said outer wall section when it is moved forwardly, and means for adjusting said section axially between a coextensive position with the rest of said outer nozzle wall and a. position in contact with the inner wall of said annular nozzle.

2. In combination with a jet propulsion power nozzle, a mechanism for regulating the speed of Jet-propelled aircraft by regulating the relative portions of the discharge, which are directed in the normal and reverse directions, as defined in claim 1, wherein the external diameter of said flange is no greater than the maximum diameter of said nozzle.

3. In combination with a Jet propulsion power nozzle, a mechanism for regulating the speed of jet-propelled aircraft by proportioningthe amount of the discharge directed in normal and reverse directions without changing the rate of combustion, as defined in claim 2, wherein said movable section extends for approximately half the length of said nozzle.

4. In a jet propulsion power unit having a convergently directed annular discharge nozzle, an axially adjustable funnel with an outwardly turned trailing flange forming the tail end of said nozzle, and control means for axially adjusting said funnel forwardly to more or less restrict the jet discharge in the rearward direction 4 while increasing its discharge in the forward direction without changing the rate of combustion.

5. In combination with a Jet propulsion power unit having a convergently directed annular discharge nozzle, an outwardly reversely curved flange funnel, shaped and positioned to form an extension of the outer wall of said nozzle for full rear discharge, means for moving said funnel forwardly to a position where it will impinge on the inner convergent wall of said nozzle for complete reversal of the discharge, and to intermediate positions for proportionate reverse directional discharge without combustion rate changes.

6. In combination with a jet propulsion power unit having a convergently directed annular discharge nozzle, a thrust reversing device -adjust-- able to any proportionate amount of forward or reverse thrust as deflned in claim 5, and a remotely controlled motor for adjusting said device.

7. In combination with a jet propulsion power unit having a convergently directed annular discharge nozzle, a remote controlled Dower oper able mechanism as defined in claim 6 wherein said longitudinally movable funnel is sealed by contact against discharge leakage at either the extreme forward or rearward position.

ARNOLD W. MARTIN.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 2,243,800 Goodyear May 2'1, 1941 

